RuntimeError at /host You called this URL via POST, but the URL doesn't end in a slash and you have APPEND_SLASH set. Django can't redirect to the slash URL while maintaining POST data. Change your form to point to 127.0.0.1:8080/host/ (note the trailing slash), or set APPEND_SLASH=False in your Django settings.
原因:
表单action字段没有以 '/' 结尾
action 修改为 action="/a/b/"即可修复